1、副词 adv.1.坐火车 坐火车 take a train “坐火车”。

2、动词短语.by train “坐火车”。

3、介词短语用作方式状语. I’m afraid that something would go wrong with the plane. 火车装运 by sea freight 海运.by train 火车装运.by truck 卡车装运She came by trainHours by air or days by trainShe prefers traveling by train。